


The End Of The Beginning

by VampAmber



Series: SPN ABO Bingo: Round One [14]
Category: Supernatural
Genre: Alpha Castiel (Supernatural), Alpha/Beta/Omega Dynamics, Castiel Loves Dean Winchester, Dean Winchester Loves Castiel, Dean in Heat, Episode: s05e04 The End, Heat Sex, M/M, Mating Cycles/In Heat, Omega Dean, Porn With Plot, Porn with Feelings, SPN A/B/O Bingo, Smut, To Be Continued
Language: English
Status: Completed
Published: 2017-10-29
Updated: 2017-10-29
Packaged: 2019-01-26 06:30:25
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,885
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/12551264
Author URL: https://archiveofourown.org/users/VampAmber/pseuds/VampAmber
Summary: He just wished that Zach-y boy had picked a better time. Dean could feel those deep seated aches in his abdomen that could only mean he was a day or so away from his damn heat starting. Hopefully he could learn his little lesson before he had to lock himself away for a few days to keep himself from presenting to every damn alpha in a five mile radius. He usually took suppressants, but dealing with Lucifer had kind of taken front seat just long enough for Dean to miss a few too many doses. “Damn it,” he muttered to himself as he rubbed at his wrists, finally free.He wandered out to see where the hell he was. It was an old summer camp, that much he could tell, but that was about it. But as weird as all this was, as unreal and impossible as it had to be, the most mind blowing part was definitely Cas. Fuzzy, stoned out of his gourd, sex guru to a gathering of betas and omegas Cas. Cas, who smelled so strongly of alpha and everything that Dean had ever wanted that he had to shift himself when the guy wasn't looking to try and hide the quickly growing erection in his pants, praying that he wouldn't slick right through his jeans.





	The End Of The Beginning

**Author's Note:**

> This was originally going to be the first chapter of a longer fic, but I figured out if I split it up into two smaller fics, not only could I get this one out faster (the second chapter is currently kicking my ass as far as writing is concerned), but I could also knock out two squares instead of one because I'm a cheap bitch that way. *evil grin* This one can totally be read as a stand alone, as well. So yay there.
> 
> The square I used for this fic was **Rut/Heat**. Enjoy the porny bits. ^_^

This wasn't real. There was no way this could be real. Zachariah must've pulled something like that Sandover office building bullshit again, because there was no fucking way that Dean was actually in the future right now, and that the future was… this.

He looked around at the post-apocalyptic ruins surrounding him and shuddered. He expected Snake Pliskin to be swinging by to save the president at any moment, or some Mad Max shit. There was no way this was real.

And running into the Croatoan zombie only reinforced in him the certainty that none of this was really happening. He’d just pretend to learn whatever stupid lesson that dick with wings was trying to teach him, and then wake up from this bizarro dream in his crappy motel bed.

And as he stared up at himself, the future version at least, he couldn't help but feel a little insulted. Was this really how Zachariah thought he should be? The douche was just as bad as most of the angels Dean had met. He was as stupid as most of those angels, too. Took his lockpicks, but didn't think to keep him from digging nails out of the floorboards. Yeah, definitely not real.

He just wished that Zach-y boy had picked a better time. Dean could feel those deep seated aches in his abdomen that could only mean he was a day or so away from his damn heat starting. Hopefully he could learn his little lesson before he had to lock himself away for a few days to keep himself from presenting to every damn alpha in a five mile radius. He usually took suppressants, but dealing with Lucifer had kind of taken front seat just long enough for Dean to miss a few too many doses. “Damn it,” he muttered to himself as he rubbed at his wrists, finally free.

He wandered out to see where the hell he was. It was an old summer camp, that much he could tell, but that was about it. But as weird as all this was, as unreal and impossible as it had to be, the most mind blowing part was definitely Cas. Fuzzy, stoned out of his gourd, sex guru to a gathering of betas and omegas Cas. Cas, who smelled so strongly of alpha and everything that Dean had ever wanted that he had to shift himself when the guy wasn't looking to try and hide the quickly growing erection in his pants, praying that he wouldn't slick right through his jeans.

As much as Dean would never admit it out loud, he’d actually been attracted to the nerdy angel for quite some time now. But Cas had never smelled of alpha like this, smelled so damn perfect it hurt. And now what had seemed like days til his heat was probably only a matter of hours at best. Shit.

Dean’s erection was completely forgotten when his system was flooded with more guilt than should have ever been possible, though. Cas was basically human now. Powerless, fragile, and using an amped up Winchester method for coping. Alcohol and lots of it, but adding in what seemed like just about every drug possible, legal, illegal, and shit Dean didn't even know existed until the former angel mentioned it. The omega felt like he was going to throw up, and the incoming heat only made things worse. He could see Cas sniffing at the air occasionally, with an impossible to decipher expression on his face.

“No suppressants?” Cas asked, out of the blue. Dean had been sitting on the floor, explaining how Zachariah had dumped him here, while the stoned ex-angel had been casually getting in those sniffs. No point in lying to him, because he was sure it was obvious by now. Cas was oozing alpha pheromones stronger than anybody Dean had ever encountered, and his own seemed to almost be reaching for them at this point.

“With all the apocalypse stuff, it kinda slipped my mind,” Dean responded, trying to make it sound like no big deal.

“Makes sense, I remember that being a pretty hectic time,” Cas said, scooting closer to Dean. The omega held in a whimper, because every fiber of his being wanted to jump the guy. It was just his heat, it had to be.

“Yeah, I should probably… lock myself up for a few days, maybe,” Dean said, his senses screaming at him. _Want! Need! Mate! Mate NOW!_ “If you guys have a place I can do that, or maybe just an empty cabin?” _Mate! Mate! Mate Cas! Mate Cas now!_ No.

“Or… I could help you?” Cas suggested, somehow managing to look sincere and lecherous at the exact same time.

“You, uh… you don't have to if you don't want to,” Dean said, starting to fidget. No longer hours, but minutes. How the hell potent of an alpha was Cas? This was miles from anything he’d ever experienced. In fact, miles were way too small of a measurement.

“Oh, but I do, Dean,” Cas said, starting to crawl towards Dean. Minutes, seconds, milliseconds. Fuck time, Dean could feel the slick already soaking through his underwear, his jeans, probably the damn rug he was sitting on by now.

“Like all those other omegas?” Dean sniped, trying to defuse the situation before it got out of hand. Because Dean wasn't sure he could ever go back to how things were if he knew what they could be like. What Cas was like. God he wanted this, but…

“No Dean, only you,” Cas said, voice rough and deep and Dean lunged forward to kiss him before his brain even finished processing the words. The ex-angel was startled, but after a few seconds he started kissing back. Dean's brain fled the scene, leaving only instinct and lust and _Cas_. Cas pushed him down onto the ground, his pants basically ruined by now, and the alpha was covering Dean's body with his own moments later.

Dean let out that held in whimper finally when he felt them connect through their clothing, and when that turned into grinding the whimper went straight to a debauched moan. “Cas,” Dean groaned, thrusting his hips in time with Cas’. Pants, why were pants even a thing? There should be no pants. “Need you,” Dean panted out. “God, I need you.”

“Always needed you, Dean,” Cas said in between bites and nips to Dean's neck. “Even back then.” There was a ripping noise and suddenly Dean was naked from the waist up, and Cas and his impossibly beautiful mouth was making his way downward, worshiping Dean's nipples with his teeth in the most mind blowing way imaginable. Dean hadn't even known that his nipples were that sensitive until just now, but he would definitely have to remember it for later.

“Wanted you,” Dean said as he struggled with Cas’ belt. “Even in that barn.” Belts, pants, shirts, they should all be illegal as far as Dean was concerned right now. “Especially in that fucking barn. Wanted you so bad.”

“Dean, you talk too much,” Cas said before silencing the omega with his mouth. They pulled apart for the exact amount of time it took to remove Cas’ shirt, then fumbled with belts and zippers and pants while their mouths were attached in a way neither of them even wanted to end. At least Dean assumed Cas felt the same, since he roughly shoved them back together whenever Dean broke off to breathe.

When all their clothing was finally, blessedly, gone, Cas pulled away and gave Dean an approving once over. “He’d never let me do something like this,” Cas muttered, starting to run his hands worshipfully down Dean’s thighs.

“Douche me?” Dean asked.

Cas chuckled, the sound husky and making Dean’s dick somehow get even harder than it already was. “He’s all about the damn mission,” the ex-angel complained, moving on from Dean’s thighs to his sides. “Won’t even fucking admit to this.” As if to prove what he meant by ‘this’, Cas bit Dean’s left hip, sucking a bruise into it and making the omega squirm and drip like a newly presented teenager.

“His loss,” Dean choked out, but only just barely. Dear god, those teeth. That mouth. That whole fucking drugged out angel of the past. Fuck.

“And my gain,” Cas purred, draping himself back over Dean’s body. “How long does your heat usually last, anyway? He takes so many damn pills that it makes me look bad.” He whispered this directly into Dean’s ear, sending a shiver down his spine and yet another whimper to his mouth.

“Three days or so,” Dean whispered back. “Please, I need you so bad Cas.”

“Well, since you’re asking nicely,” Cas said, and without warning the alpha sheathed himself inside Dean. Omegas never really had to worry much about prep, especially when they were in heat, but it was so unexpected and Cas was so big that Dean yelped.

And with that one yelp, Cas was his old self again, from Dean’s point of view. “Are you okay, Dean? I didn’t hurt you did I?”

“Just surprised,” Dean growled, and pulled the alpha back down into another heated kiss. Now that they’d gone this far, he refused to ever go back. He’d deal with the damn repercussions later.

“Mmm, bossy bottom,” Cas teased, back to his current day self once again. “I definitely like.” Then he was thrusting into Dean, and the omega’s vision was going hazy with the pleasure of it.

The room was already drenched in their combined scents, and Dean wanted nothing more than to bottle it up and bathe in it for the rest of his life. He ran his nails down Cas’ back, not even trying to be gentle. He wanted it hard, he wanted it so hard that he’d be feeling it until his next damn heat in six months, and he was babbling this fact over and over again. Cas was biting at any available surface of Dean’s skin, sucking bruises but not going so far as to leave a mating bite. Dean felt disappointed at that, and had to repeatedly remind himself how bad that would be. Would a mating bite even work in this dream illusion thing? Before he could wonder about that any further, he let out a shout as he felt Cas’ knot catch and his own orgasm racked his body with wave after wave of sensations so intense he wasn’t sure if anything was real any more.

Cas collapsed on top of Dean, trapping Dean’s release between them, just as Cas was now trapped inside of Dean for the next half hour or so. The frantic bites from before turned into slow, gentle kisses. Cas ran his hand along Dean’s cheek reverently. Whatever he’d been high on when Dean first entered the cabin seemed to have been flushed out of his system, because the vibrant blue eyes that stared into Dean’s weren’t even slightly unfocused now. Dean gave as good as he was getting, gentle kisses-wise.

“I think I started falling in love with you in that barn as well,” Cas whispered, peppering light little pecks over Dean’s nose.

Yeah, Dean was never coming back from this. “You didn’t show it very well,” he tried joking. This was getting a little too serious for him, truth be told.

“I didn’t understand it yet,” Cas said, giving Dean a shy smile, the stoned hippie sex god gone completely. “It took all this for me to understand it for what it was.”

“And he, me, he never?” Dean asked, making a face at how eloquent he was being right now.

Cas shook his head sadly. “You know how you were back then, when you were you.” Dean nodded, wishing he hadn’t tried so hard to repress his feelings towards the angel back in the present. “After Sam,” Cas paused, as if gathering his thoughts. Maybe the drugs weren’t all the way gone yet? “After he said yes, you… broke. Wouldn’t let anyone close. He probably hasn’t even hugged anybody since Bobby.” Or maybe it was just really hard to talk about.

“I’m sorry,” Dean apologized for his future self.

“It’s not your fault, at least not yet,” Cas said back. He moved them so that they would both be more comfortable, then nuzzled into Dean’s neck. It was so much like how mated couples acted that Dean had to remind himself that whatever was happening to him wouldn’t last. This dream world would eventually pop and this version of Cas, real or imaginary it didn’t matter, would never exist again.

Dean nuzzled him back anyway, wanting to comfort Cas more than ever. The guilt from earlier returned, reminding him of how broken the alpha he was connected to truly was. “I promise, I’ll make it better. I won’t let this happen to you. I’d rather die first.”

Cas moved his head so he was staring into Dean’s eyes. There was so much pain and emotion behind the blue that Dean almost didn’t recognize them. But no matter how much they changed, Dean would always know Cas.

“And tell him,” Cas pleaded, holding Dean’s gaze. “Tell him, tell me that you feel it too. Please?”

“I promise, Cas,” Dean said, putting his hand on Cas’ cheek. He kissed the ex-angel slowly, trying to put his sincerity into it.

When Dean’s heat overwhelmed him again an hour later, the pounding pace was replaced with the sweetness of those shared kisses, and somehow that was even more incredible than the first time.

Dean spent the rest of his heat in Cas’ cabin, much to the great, loud, and repeatedly expressed displeasure of the future version of himself. But that guy was a dick on par with Zachariah himself, so he could shut the fuck up as far as Dean was concerned. At least he was smart enough to be insulted when Dean told him just that when the guy walked in on him and Cas for the third time that day near the end. Dean and Cas alternated between the slow sweetness of the second time, and the frantic desperation of the first, but even when Cas was pounding the omega into the mattress to the point of destroying part of his wall from the bedframe hitting it so hard and so often, there was still that underlying sweetness.

As soon as the ‘stench of my whore past self’s heat’ was gone, according to his future self, a meeting was called for the entire camp. Future Dean had gotten a lead on where Lucifer was a few days ago, but had waited until him and Cas were done before sharing it. Dean knew himself enough to see that tiny flash of jealousy pass over his features, but in less than a second it was gone and he was back to filling everybody else in on his plan while still getting in as many insults as he could to his past self. If he wasn’t mistaken, Cas had seen it as well, but they were the only ones since it was impossible to spot if you didn’t know him as well as they did. But neither future version mentioned anything about it, and everybody went to work preparing for the mission that would happen the next day. Dean wasn’t sure if the Colt would really be enough to take down Lucifer, but he at least agreed with douche him that it was their only option at this point.

Dean slept next to Cas that night, even though he no longer had the excuse of his heat. He was pretty sure that had pissed off his future self, and it was like the sprinkles on top. After three frenzied days of marathon sex, they ended up only cuddling that night, and as much as Dean refused to admit liking chick flick moments, he thought that he actually preferred the cuddling.

When his future self called out vehicle assignments, he placed Dean and Cas together. That little flash went across his face again, but Dean was again certain that only he and Cas had noticed. And this time, he wasn’t going to let it rest.

“What’s the deal with other me?” Dean demanded once they started on the long drive to what was supposed to be Lucifer’s encampment

“Not sure what you mean, Dean,” Cas replied, not taking his eyes off of the road. It was beyond obvious, though, that he knew exactly what Dean meant and was just avoiding the question.

“Dude’s little jealousy look he keeps giving us,” Dean said.

Cas stayed silent for so long that Dean thought he wasn’t going to answer. But then he spoke up, sounding melancholy. “Well, he is you, what you would’ve become. So it only makes sense that he loves the same as you.” Cas reached over to grab Dean’s hand, and their fingers slid together like they’d been made solely for that purpose.

“Then why didn’t he say something?”

“Why didn’t you?” Cas countered, making Dean swear under his breath.

“Fine, point taken.” The rest of the ride went in silence, but it was the comfortable kind, just like they always used to have. The only difference was the still sensitive spots from the faded hickeys all over Dean’s body, their combined scents even though they’d both showered since the last time Cas had knotted him, and those clasped hands that meant more than anything else on the planet to Dean right now. He tried to think of everything that he could that didn’t involve this reality, and the man in the seat next to him, no longer existing soon. Maybe it all being a dream would be for the best…

His future self pulled him aside as the rest of the team members, a sober yet just as scruffy Cas included, got ready to rush into the _fucking obvious trap_. “Enjoy your little romantic road trip?” He asked his past self sarcastically.

“Yeah, we’re thinking of hitting up Vegas later, make it more official,” Dean said back. “Ya jealous?” There was just something about future him that made Dean feel antagonistic.

And then the angry facade finally fell. “I wanted him to have one last bit of happiness, and I knew I couldn’t give it to him myself.”

Dean’s mouth dropped open like a cartoon character. He could never in his entire life remember being that open and honest and vulnerable, even to himself, whether metaphorically, or in this case literally. And then the truth of the situation hit Dean in the face like an eighteen wheeler at high speed. “This is a suicide mission.” It wasn’t even a question.

“This world, all the messed up shit that happened, it was all my fault. And damn it, I’m going to fix it,” his future self said, and Dean had never wanted to hurt himself as badly as he did right now. Just one punch. Or ten. Only a few dozen punches.

“So you’re just gonna throw ‘em all into the damn meat grinder? Gonna let Cas go off to die? You fucking love him and yet you’re still okay with this plan?” Dean was so angry he was seeing red around the edges of his vision. He knew he had major guilt issues, and that he could be an asshole even when he wasn’t the guy standing in front of him, but this? It sickened him that any part of him, even a part that didn’t technically exist yet, would ever think this was okay.

“It’s the only way,” he said, sounding and looking completely defeated.

“Only way or not, they should still be given a damn choice,” Dean all but shouted. “Letting volunteers go off and die like that is bad enough, but you lied to them. You’re leading them like the damn sheep to the slaughter.”

“They would’ve agreed anyway,” his dickbag future self tried to reason, but Dean was having none of this. This guy was making Uriel look compassionate and empathetic.

“And what, asking them to make sure was just too much of a hassle?”

“You don’t understand,” the asshole tried again, but Dean was done.

“No, I think I do. And I’m gonna go out there and make sure every single one of them understand, too.” Dean brushed past the monster that he had become, then suddenly there was a sharp pain and the world went dark.

He woke up minutes or hours later to the sounds of screaming and gunshots. Then, as if a switch was flipped, everything went silent. “That son of a bitch knocked me out,” Dean grumbled to himself, rubbing at the lump on the back of his head as he started walking towards where he thought his future self had been planning on heading.

He’d picked the right direction, because there was his brother filled up with Satan himself, with his pristine shoe on future Dean’s neck. Before he could react, though, not-Sam’s foot moved and there was a sickening crack. Nothing like watching yourself die to make you feel like vomiting up everything you had ever eaten in your entire life.

“You never really had a chance, you know,” the fallen archangel wearing his brother as a meat suit said casually, as if commenting on the weather. “Pity, really.”

There were words exchanged, Dean knew there were. He was just so sick and angry and hopeless and a million other emotions all at once that they flew around him, his and Lucifer’s, and yet all he could see were his own dead eyes staring up at him. At least the guy was with Cas now.

And then, like the worst nightmare that could ever exist, Dean was waking up in the bed he’d fallen asleep in the night before or almost a week ago, he could no longer keep track. Had it all been a dream? The marks Cas had left that first day had already faded before they even stepped foot into that truck, and there wasn’t much else that would be easily identifiable. He was back in his clothes from before, but he’d seen the kind of stuff Cas could do with clothing, making blood stains and bullet holes disappear like they’d never existed in the first place, so even that couldn’t tell him one way or the other. And then that dick with wings Zachariah was fluttering in, his smugness making Dean feel like vomiting all over again, and finding proof took a back seat to arguing.

Dean had to stop himself from crying when he was suddenly standing in front of Cas by the side of a road, both out of relief that he was no longer within punching distance of that bald sack of shit, but mostly because Castiel, proper angel of the lord and not a broken shell, was standing in front of him. He tilted his head, looking justifiably confused, and Dean had to stop himself from throwing himself at the alpha and covering him with kisses. He may have promised the angel’s future version that he would tell him how he felt, but for now that could wait. Instead, he just told Cas “Don’t ever change” and promised himself that he’d say the rest later.

**Author's Note:**

> Fair warning: the square I plan on using for the continuation will be my "Unplanned Mpreg" square. Just so you know. XD


End file.
